Window and interacting roof seal assemblies for motor vehicles are generally well-known in the art. Conventional side doors for passenger vehicles include a structural member that extends around the top of the side window, typically referred to as the door frame. Among other things, the door frame provides support for glass weather seals that in turn provide support and sealing function to the door glass when it is in the up position. However, some vehicles employ so-called “frameless” door systems that do not have any structural member above the belt line to support the glass. These are typically used on vehicles with folding or removable (convertible) tops, so that when the top is stowed and the side windows are down, there is unobstructed view out of the vehicle. Frameless doors are also sometimes used on coupes and sedans to achieve certain styling objectives.
On vehicles with frameless door systems, the upper edge of the door glass typically mates with a weather seal that is mounted to the vehicle body at the forward pillar on the side of the windshield (so-called “A” pillar) and a weather seal mounted on the folding or convertible top to provide the sealing function. To maintain the ability to open and close the door without interference, the glass must be able to swing into and out of engagement with this weather seal freely. This structural limitation, however, presents challenges to achieving desired water and air leakage (wind noise) performance, particularly at high vehicle speeds (above 80 MPH). At these high speeds, aerodynamic loads on the glass tend to pull the glass away from the body, potentially reducing the seal between the glass and the weather seal (also known as glass “blow out”). Previous generations of frameless door systems relied on significant inboard preload of the glass into the body and top mounted weather seals to provide adequate sealing pressure and resistance to aerodynamic glass “blow out.” However, high levels of preload can cause premature weather seal wear during glass cycling, as well as other undesirable issues.
More recent systems have adopted an “indexing” window regulator system. Generally, these systems lower the door glass a short distance when the door is opened, then fully close the glass again when the door is closed. This changes the path of the upper edge of the glass such that it avoids interference with the weather seal retainer structure and provides a vertical gap with the weather seal structure to maintain good door openability and operation, yet allows the glass and a weather seal structural member to resist aerodynamic loads on the glass. These systems usually rely on the electronics in the vehicle that control the window regulator motor in order to lower and raise the glass based on defined input trigger(s). The most common trigger mechanism for such indexing systems is a change in the door ajar switch state, which provides a true signal that the door is opening/closing and which is incorporated as a component of the hardware and electrical systems on almost every existing vehicle for actuation of courtesy lighting.
However, despite the functional improvements that indexing glass systems provide to frameless door systems, the trade-off between effective glass engagement with the weather seal structural member and door openability remained. Potential interference may occur with such indexed designs when the door is opened quickly using the outside door handle. That is, the door and glass may be moving to the open position before the glass-index trigger activation responds and the system may not respond quickly enough (due to module wake up and computational time, physical reaction of the window system, etc.) to overcome upper edge glass-to-weather seal structure interference. While it may be possible to alleviate this situation by triggering the indexing function earlier in the door opening event (i.e., activation of or proximity to the outside door handle), alternate trigger methods tend to involve sensors that add cost, complexity, and package constraints to a vehicle. It may also be possible to trigger the indexing function earlier using existing hardware by judging a customer's intent to open a door (i.e., an unlock command from a variety of sources), but these methods are not always used when opening a door, and it is not possible to predict which door will be used, so all door glass must be indexed. This may cause higher levels of wear on the window systems, as well as unintended water entry into the vehicle, as the windows would need to stay down for some set time period to allow the customer to open the door.
Another consideration with a significant upper glass edge to weather seal structure interference is door function when the glass fails to index down (i.e., door glass frozen in place due to ice, dead vehicle battery, or failure within the electrical or mechanical system). In the case of these low probability events, although higher efforts or some noise or vibration upon door opening may be acceptable, door closing effort may become an issue. On door closing, the door glass could impact the outside of the weather seal structure, potentially causing damage or failure of the glass, weather seal structure, or other components, or, at a minimum, causing a substantial water leak path.
The ideal frameless door system offers minimal door opening effort with no noise, vibration, or harshness at any door opening speed, while also providing sufficient engagement between glass and seal structure to resist aerodynamic loads under all potential glass to weather seal tolerance conditions. Hence, a glass positioning device for vehicles having frameless doors to achieve exceptional high speed wind noise performance, while retaining acceptable door openability when the vehicle is stopped at any door opening speed, while also doing so at minimal cost which overcomes these drawbacks, would be advantageous.